(a) Technical Field of the Invention
The present invention relates to a design of rechargeable hearing aid, particularly to an improvement of hearing aid, which is derived from the modem ones and can be recharged to facilitate the user to operate. Meanwhile, the costs of batteries can be minimized and the life of use of the hearing aid can be lasted.
(b) Description of the Prior Art
Hearing aid is a great invention to those with bad faculty of hearing. Hearing deficiencies can be caused by tympanitis, living long time in harsh noise, inherent reasons, disease or inbred deficiency, aging, accidence, injury, medical hurt, etc. Fortunately, most people with bad faculty of hearing can be helped by the hearing aid. Hearing aids of various function and features can satisfy different degree of hearing deficiency. Hearing aids nowadays are even programmed to make response to micro-sound, so as to transmit more clear and melodious sound to make the user better understanding.
However, most rechargeable hearing aids of prior art is provided with a depression for receiving the battery which is connected to a liftable pivot. When the power is insufficient and the battery need be renewed, the user must open the small element carefully, take out the consumed battery and renew the battery. These operations are inconvenient to those aged who are the greatest group using the hearing aids. The disadvantages could be:                1. The parts of the hearing aid are too small to be held in hands by those aged, given the blurred vision and shaking hands.        2. The size of the batteries for the hearing aid is overly small, rendering hard recognition of the negative and positive contacts. Therefore, wrong installation would happen all the time and make the batteries get stuck. If the cover is further affixed by force, the locking pin would be broken, shortening the life of use of the hearing aid.        3. The battery for conventional hearing aid used to contain small volume and would be consumed in five days in the case of six hours a day, or 3.75 days in the case of eight hours a day. At this rate, each user would consume about 100 batteries per year, each battery for US$3, costing US$300 per year. This is apparently uneconomic!        4. The estimated 100 batteries per year for each user would render a problem in environment, in case those consumed batteries are not properly recycled.        5. If the hearing aid is power insufficient in use, such as in the cinema, out for picnic, or ride at night, there is difficulty for the user to take the hearing aid to a place under the light for change of batteries. The inconvenience caused by temporary hearing inefficiency is also bothersome.        
In view of the above, the invention provides a hearing aid structure without interference by the outside environmental cause.